Soundcloud integration design is not centered and too big

Since the new Ghost update the design of soundcloud cards is not correct anymore, see https://paul.wellnerbou.de/ukulelen-ag/

I’d expect it to behave similar as before: centered, but not so big and not overlapping the right margin.

This worked before, but the preview in edit mode was broken since the new version, so I re-added the soundcloud links and now the design changed.

I’d consider this as bug, but is there a css fix I can apply? I could not find a workaround, still trying.

Thanks!